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Game 62, Mariners at Rays

The M’s pulled out another win yesterday as Alex Cobb continues to struggle. With Cobb, Jake Odorizzi and David Price underperforming their peripherals, you could make the case that Chris Archer’s the best Rays starter at the moment. Archer, the righty the Rays got from Chicago in the Matt Garza trade, has the best FIP of any starter (though they’re all bunched pretty tightly around 3.5) in the Rays rotation. He’s got an above average K rate, and while his walks have been higher than his colleagues’, the real story has been the way he’s limited HRs.

That sounds great – Archer’s been effective in a season-plus of work, but he’s struggled with HRs, especially to lefties. He’s shown Sean Green-like platoon splits coming into 2014, making right-handers look like the average pitcher, while he made all lefties something like Mike Trout or Joey Votto. This year, he’s seeing more lefties than ever, and suddenly he’s effective against them. The major change he made this year is throwing a lot more sinkers instead of four-seamers, which helps explain the rise in his GB rate, and, by extension, some of the decline in homers.

But it’s not enough on its own. Archer’s still fundamentally a fastball/slider pitcher; his career splits may have been inflated by bad luck, but he *should* have some fairly large splits. The fact that he’s given up exactly zero homers to lefties may be due to some improvement in how he uses his slider to them, but it’s much more likely to be a fluke. So far, so standard-sabermetric theory and all. That said, Archer’s slider is pretty interesting, and throughout his career, he’s struck out more lefties than righties. Archer’s slider is thrown around 87mph, about 8 mph slower than his plus fastball. It clearly breaks gloveside, as a slider would, but the thing that stands out is its vertical drop. It drops 8″ relative to his sinker, or 11″ relative to his four-seam. A splitter, like Cobb’s or Iwakuma’s, is an effective pitch to righties and lefties because the horizontal break isn’t terribly important. It’s a little bit like a sinker’s or a regular fastball’s, which should produce platoon splits, but it doesn’t. Archer’s slider may work in the same way; maybe the vertical drop essentially overwhelms the horizontal “slide” and renders it a more neutral pitch.

Note: This is a seattlepi.com reader blog. It is not written or edited by the P-I. The authors are solely responsible for content. E-mail us at newmedia@seattlepi.com if you consider a post inappropriate.